Why do we see so many ACL’s/knee injuries in NFL. A few thoughts and a bit of a task analysis!

I have no experience of the NFL, just TV and some logic. Happy to be corrected, maybe @MovementMiyagi or @LorenLandow will verify!

I’ll also refer to Rugby for comparison...

-NFL: 4 attempts to cover 10yds. An attempt is over if the player with the ball is grounded. Also allows forward passing and blocking

-Rugby: No restriction on attempts or distance targets (other than scoring), ball must go back and no blocks

So how does this change things?

NFL athletes have an increased intent to cover ground (go fast) to make the 10yd.

Speed = load

And if space disappears, they MUST attempt to find more to cover more ground (only get 4 goes) ideally without sacraficing speed.

Large cuts, also = load

This means attempting cuts/COD of high angles at high speed! Very dangerous combination to have them together = ACL risk

Rugby players: If space disappears and the only option (cut to find more space) is unachievable, there is no reason to attempt it.

A player can just go in to contact (no attempt limits) or pass (can’t slap down passes) and another phase/attempt can begin.

This means less need to attempt large cuts = less high load scenarios.

But not only is there less need to attempt them, the scenario to consider them is less frequently presented than in NFL

But firstly, the NFL game structure affords more speed to the attacker...

NFL: certain players roles (e.g offensive line) are to create space for the ball carrier.

Space = Speed
Speed = Load
Load = Risk - especially when that space suddenly disappears and a cut is needed.

But why would that space be more likely to disappear?

Due to defensive formation (covering fwd pass) when initial space is given (blockers) and speed is achieved, there are more defenders in the backfield who can cut that space off.

Meaning that large cuts need to both be considered and attempted, even once speed has been achieved

Rugby: Defensive line holds position, reducing space and therefore the chances of initial high speed.

Less load

Rugby also has a structure with the defensive line where once an athlete had broken through, there are less space constraints (more likely 1:1) meaning less likely to need to cut to a large angle.

This is because a defensive formation isn’t needed to cover fwd passing so more players pressing

More initial space constraints = lower starting speed, and less space constraints if broken through defensive line = shallow cut = lower load for both reasons!

So not only is NFL structured to AFFORD more initial speed (blockers) and REQUIRE more speed (distance target), it also AFFORDS more high angle cutting (backfield defenders) and REQUIRES more high angle cutting (4 attempts).

All increasing joint load & risk

Lots of other influencing factors obviously, but this just further supports the need for COD and Deceleration assessment in that population IMO.

If players are better at braking to slow down in a small amounts of time, load is lowered and cuts are more likely completed

Lucky I have a solution to that isn’t it?!